Characterisation of β-Thalassaemia Mutations Among Haematology Patients at Aminu Kano Teaching Hospital

Beta-thalassaemia is caused by mutations in the HBB gene that reduce or abolish beta-globin chain synthesis, leading to haemolytic anaemia of varying severity. Although less studied than sickle cell disease in Nigeria, beta-thalassaemia mutations have been reported in certain Nigerian ethnic groups, particularly among populations with historical links to the Mediterranean and Middle East. This study characterised HBB gene mutations in patients presenting with microcytic anaemia and elevated HbA2 levels at Aminu Kano Teaching Hospital, Kano State. Forty patients with suspected beta-thalassaemia trait or disease were enrolled alongside 40 healthy controls. DNA extraction from peripheral blood was followed by Sanger sequencing of the HBB gene coding region and splice site regions. Capillary electrophoresis haemoglobin quantification was used to determine HbA2 and HbF levels. The IVS1-1 (G>A) splice site mutation was the most frequently detected variant in this cohort, alongside rare compound heterozygotes. These findings contribute to documenting the molecular spectrum of beta-thalassaemia in Northern Nigeria and have implications for newborn screening programme design in Kano State. Keywords: beta-thalassaemia, HBB gene, Sanger sequencing, Kano State, haemoglobinopathy